Unsolicited mail is not a new concept; unsolicited mail has been around for decades and arrives through paper mail delivered by postal mail or by hand to people's mailboxes. The unsolicited mail typically is advertising or promotional materials of a commercial nature. While providing a way to communicate information, the practice has become known generally as “junk mail” because in most instances the unsolicited mail is thrown away, or “junked” as not relevant to the addressee. Significant amounts of money are spent on preparing and delivering of commercial messages for the potential of a small percentage of responses.
The communication of unsolicited commercial messages has recently migrated into preparation and distribution of electronic mail (“e-mail”) communicated through networked computer systems and delivered via e-mail servers into addressee's e-mail boxes. Generally, the costs for the advertiser using electronic mail is lower, which reduced costs arise primarily from the reduced distribution expenses. However, the burden of the unsolicited messages is borne by others. This includes network providers who establish and maintain network capacity for handing messages. Addressees must sort through incoming e-mail to identify desired e-mail from unwanted e-mail and delete the unwanted e-mail. Some e-mail recipients receive daily a significant volume of unsolicited e-mail communications (for example, some recipients receive hundreds, if not more, unsolicited e-mail daily). Any unsolicited e-mail is referred to in the messaging trade as “spam” mail. Such electronic mail of a commercial nature occupies bandwidth, cancels delivery of messages, and upon delivery takes recipient's time to sort and delete unwanted messages. Persons who engage in the transmission of large volumes of unsolicited mail are referred to in the industry as “spammers” and that term is used herein.
Messaging systems use a hierarchical addressee naming system with a plurality of domain names that allow both people and computer machines to determine where to send the message traffic. This is true whether visiting a website on the network or sending an e-mail to a recipient. For every domain in the domain name system, there is a set of name servers that can be defined at the domain registry. These servers are known as “authoritative name servers”, and are the final authority for use in resolving DNS requests for a domain.
Resolving a DNS request for a domain name is a common activity in messaging, regardless of whether the message being sent is sent by a “spammer”, or the sender has a legitimate reason to send an e-mail message to a given e-mail address. For each e-mail message, a DNS query must be made for the domain name to determine the messaging network address that identifies how to route the e-mail message.
There have been many attempts to thwart unwanted e-mails. However the current systems are resource intensive and suffer from degraded effectiveness due to concerns about false positives on identifying desired e-mail from unsolicited and unwanted e-mail. These current techniques for stopping unsolicited electronic mail typically involve evaluating the messages for sender and/or content. Some systems conduct a check of the sender's network address or identifier against a current list of known commercial e-mail distributors or “spammers” using the real-time DNS blacklists. These lists are generated by interested persons and published for information and use in the messaging networks. Other systems filter the messages based on message content. These techniques are conducted by the server at which mail is received for distribution to an e-mail recipient associated with that server. Other filtering techniques occur at the client or e-mail recipient level. These often permit the e-mail recipient to adjust the selectivity of the technique in filtering e-mail. While these techniques intercept many unsolicited e-mails, there are drawbacks. These techniques generally slow the transmission and distribution of messages through the network, and thus can block or delay legitimate e-mails. Furthermore, spammers learn what techniques are in use and change their practices accordingly, causing blocking techniques to become outdated and ineffective.
Accordingly, there is a need in the art for an improved apparatus and method for controlling the flow of unsolicited e-mail messages within a messaging network by distinguishing between requests from legitimate e-mail sources and requests from unsolicited e-mail sources and routing of the message traffic based on that differentiation. It is to such that the present invention is directed.